Due to advancements in telecommunications and data transmissions speeds over balanced, twisted-pair cables, the connectors (such as jacks, plugs, patch panels, cross connects, etc.) are now a critical impediment to high performance data transmission at higher frequencies. Performance characteristics, particularly crosstalk and return loss, degrade beyond acceptable levels at higher frequencies. This degradation is particularly true for system operation at category 6 and category 6A levels.
When an electric signal is carried on a signal line that is in close proximity to another signal line or lines carrying a signal or signals, such as in the case of adjacent pins of contacts in the connector, energy from one signal line can be coupled into adjacent signal lines by the electric field generated by the potential between the two signal lines and the magnetic field generated as a result of the changing electrical fields. This coupling, whether capacitive or inductive, is called crosstalk.
Crosstalk is a noise signal that degenerates the signal-to-noise margin or ratio (S/N) of the system. In telecommunication systems, reduced S/N margins result in greater error rates in the information conveyed on the signal line. The S/N margin must satisfy set performance criteria for the system category involved.
Crosstalk problems could be overcome by increasing the spacing between the signal lines, or by shielding the individual signal lines. In many cases, the wiring is preexisting and standards define the geometries and pin definitions for connectors, making the necessary changes to such systems cost-prohibitive. In the specific case of communication systems using balanced, twisted-pair wiring, standards defining connector geometries and pin out definitions are in effect, but were created prior to the need for high speed data communications.
These standards have created a large base of wiring and connectors and a need for connectors capable of meeting the requirements of high speed communications, while maintaining compatibility with the original connectors. The standard connector geometries and pin outs are such that a great deal of crosstalk occurs at higher signal frequencies.
Numerous connector constructions have been developed to address crosstalk problems. Minimizing near end cross talk between the signal lines of an individual connector typically involves counteracting a noise signal in a line by inducing in that line a signal equal to and opposite to the noise signal such that the induced noise signal is effectively cancelled by the induced correction signal. Examples of such connectors are disclosed in U.S. Pat. Nos. 5,432,484, 5,673,009 and 6,796,847, the subject matter of each of which is herein incorporated by reference. Alien crosstalk between the conductors of adjacent connectors has been addressed by applying separate dedicated shielding components around individual connectors. See, e.g., patent application publication No. US 2009/0098777.